make generator expressions consume all following comma-separated expr…

…essions

doc/manual/arrays.rst

@@ -224,25 +224,28 @@ demand, instead of allocating an array and storing them in advance
 (see :ref:`_man-interfaces-iteration`).
 For example, the following expression sums a series without allocating memory::
 
+.. doctest::
+
  julia> sum(1/n^2 for n=1:1000)
  1.6439345666815615
 
-When writing a generator expression with multiple dimensions, it needs to be
-enclosed in parentheses to avoid ambiguity::
+When writing a generator expression with multiple dimensions inside an argument
+list, parentheses are needed to separate the generator from subsequent arguments::
 
- julia> collect(1/(i+j) for i=1:2, j=1:2)
- ERROR: function collect does not accept keyword arguments
+ julia> map(tuple, 1/(i+j) for i=1:2, j=1:2, [1:4;])
+ ERROR: syntax: invalid iteration specification
 
-In this call, the range ``j=1:2`` was interpreted as a second argument to
-``collect``. This is fixed by adding parentheses::
+All comma-separated expressions after ``for`` are interpreted as ranges. Adding
+parentheses lets us add a third argument to ``map``::
 
- julia> collect((1/(i+j) for i=1:2, j=1:2))
- 2x2 Array{Float64,2}:
- 0.5 0.333333
- 0.333333 0.25
+.. doctest::
 
-Note that ``collect`` gathers the values produced by an iterator into an array,
-giving the same effect as an array comprehension.
+ julia> map(tuple, (1/(i+j) for i=1:2, j=1:2), [1:4;])
+ 4-element Array{Any,1}:
+ (0.5,1)
+ (0.333333,2)
+ (0.333333,3)
+ (0.25,4)
 
 .. _man-array-indexing:
 

src/julia-parser.scm

@@ -1474,10 +1474,7 @@
  ((eqv? c closer) (loop (cons nxt lst)))
  ((eq? c 'for)
  (take-token s)
- (let ((gen (parse-generator s nxt #f)))
- (if (eqv? (require-token s) #\,)
- (take-token s))
- (loop (cons gen lst))))
+ (loop (cons (parse-generator s nxt) lst)))
  ;; newline character isn't detectable here
  #;((eqv? c #\newline)
  (error "unexpected line break in argument list"))
@@ -1532,11 +1529,8 @@
  `(dict_comprehension ,@(cdr c))
  (error "invalid dict comprehension"))))
 
-(define (parse-generator s first allow-comma)
- (let ((r (if allow-comma
- (parse-comma-separated-iters s)
- (list (parse-iteration-spec s)))))
- `(generator ,first ,@r)))
+(define (parse-generator s first)
+ `(generator ,first ,@(parse-comma-separated-iters s)))
 
 (define (parse-matrix s first closer gotnewline)
  (define (fix head v) (cons head (reverse v)))
@@ -1968,7 +1962,7 @@
  ex))
  ((eq? t 'for)
  (take-token s)
- (let ((gen (parse-generator s ex #t)))
+ (let ((gen (parse-generator s ex)))
  (if (eqv? (require-token s) #\) )
  (take-token s)
  (error "expected \")\""))

test/parse.jl

@@ -347,3 +347,5 @@ end
 # issue #14683
 @test_throws ParseError parse("'\\A\"'")
 @test parse("'\"'") == parse("'\\\"'") == '"' == "\""[1] == '\42'
+
+@test_throws ParseError parse("f(2x for x=1:10, y")